Colorful fluorescence is the calling card of another
rare-earth element with another odd name: europium. Elements were frequently named for the town
or region where they were discovered, sometimes in a
very provincial manner, as was the case with yttrium.
Europium runs against the trend. It was the last of the
natural lanthanides to be found, in ;;;;. In that year,
Frenchman Eugène-Anatole Demarçay isolated the element as an impurity in samples of another rare earth,
samarium (named, indirectly, after Russian mine o;cial
V. E. Samarsky-Bykhovets). In a ;t of magnanimity, Demarçay decided to name his element not after Paris, where
he worked, or after France,
but in honor of all Europe.
Of
;;; ;;; ;;;; ;;;;;;, ;;;;-
pium is perhaps the most visible. It is used in the phosphors
of display screens, where it
emits red and blue light. A
little europium is also added
to mercury vapor streetlamps
to whiten their otherwise
cold blue light. It even has found its way into the wallet.
O;cials at the European Central Bank evidently decided
it would be fitting if europium-based compounds were
added to euro banknotes as ;uorescent security markings.
When the notes are inspected under a bank’s ultraviolet
scanner, pictures of a bridge and the European continent
light up in green. The relationship between europium
and the euro was not announced; it was revealed only
when Freek Suijver and Andries Meijerink, two curious
chemists at the University of Utrecht in the Netherlands,
put the notes into their spectrometer. ;ey had a good
laugh but were unable to determine who concocted this
sophisticated inside joke. “I learned that the use of europium was intentional,” Meijerink says, “but I am sorry to
say that I have no inside information on who, where, and
how it was decided to use the europium luminescence.”
PABLO CASTAGNOLA/REDUX
;e importance of the rare earths is no secret in the
industrialized world, however. One year ago, when China
announced it would limit exports, the commodity price
of all the rare earths almost instantly shot up. In just
six months the price of samarium oxide quadrupled, to
more than ;;; a pound in May of this year, owing to its
property as a permanent supermagnet when alloyed with
cobalt. Samarium’s ability to stay strongly magnetic in
extreme temperatures makes it a favorite of the military
for use in precision-guided weapons. In April, China took
steps to keep prices high by extending a national ban on
rare-earth exploration and the opening of new mines.
For all the dire headlines, the latest rare-earth frenzy
may be little more than a bubble. Not so long ago, China
aggressively pursued cheaper means of isolating rare
earths, benefiting from the absence of costly environ-
mental regulations, which is how the country acquired
its current near-monopoly. But its dominance could well
be temporary. “Because of its cheap prices, the competi-
tors closed down,” says Pekka Pyykkö. “In the present
situation, new capacity will undoubtedly be restarted.”
Mountain Pass, California, is one of the places where
American rare earths may rise again. Here, Molycorp used
to meet much of the world’s demand for these elements.
;e company shuttered its operations in ;;;;, but earlier
this year it reopened its mine. Another American com-
pany, U.S. Rare Earths, owns mineral rights to lanthanide
resources in Montana and Idaho; according to a report by
the Government Accountability O;ce, these are in “early
exploratory stages of development.” Mines in these areas
may take up to ;; years to bring online, the report states,
“largely due to the time it takes to comply with multiple
state and federal regulations.”
A visit to other parts of the periodic table could also
turn up substitutes for some of the lanthanides. In Janu-
ary, Toyota—spooked by rising prices and supply con-
cerns—announced that it is developing a new type of
propulsion, called an induction motor, for future electric
and hybrid vehicles. ;e technology notably does not rely
on rare-earth elements.
For now, though, the world is hooked on the lanthanides, and China is the only place that has the processing capacity up and running. As for Ytterby, that mine
at least is unlikely to reopen. It is now a historic landmark,
located just off the intersection of Terbium and Mine
roads. A small sign commemorates it on the quayside,
noting the site’s prodigious contribution to chemistry.
Life on Lanthanides:
Wind Turbines
Carbon-free electricity gets a big
boost from rare earths. Behind the
rotors of a wind turbine, wire coils
move through a magnetic field
to generate current. To maximize
efficiency, manufacturers like
General Electric often use high-intensity magnets that incorporate rare-earth elements. Some
turbines contain 700 pounds of
neodymium. “Without rare earths,
you’d have to use larger, heavier
magnets, and you’d have to build a
stronger, more expensive tower to
support them,” says materials scientist Alex King of the U.S. Department of Energy’s Ames Laboratory.
Last year GE received a $2 million
federal grant to develop magnets
with only one-fifth the rare-earth
content of today’s offerings. AG
